This invention relates to an industrially excellent process for the production of a water-soluble carbodiimide using ethyl isothiocyanate and N,N-dimethyl-1,3-propanediamine as starting materials.
Carbodiimides are an industrially profitable reaction aid widely used in the overall organic synthesis because they advance an esterification reaction or an amidation reaction, as a dehydrocondensation agent, under quite mild conditions. Especially, water-soluble carbodiimides containing a hydrophilic group in the skeleton are superior to general-purpose carbodiimides because of the following advantages.
1. They can be used in the reaction in a water solvent (e.g., D. C. Hoare, et al., The Journal of Biological Chemistry, 242, 2447 (1967)). PA1 2. When used in an organic solvent, they can easily be removed by washing with dilute acid or water since the reaction residue is water-soluble (e.g., J. C. Sheehan, et al., Journal of Organic Chemistry, 21, 439 (1956)).
They are widely utilized chiefly in the synthesis or modification of peptides and phosphoric acid esters.
An ordinary method for forming water-soluble carbodiimides includes the following two methods as described in J. C. Sheehan, et al., Journal of Organic Chemistry, 26, 2525 (1961).